<style>
  div {
    position: relative;
    width: 100px;
    height: 100px;
    background: red;
    overflow: hidden;
  }
  iframe {
    position: absolute;
    height: 200px;
    width: 100px;
    border: none;
  }
</style>
Test passes if there is a single 100x100px orange square.
<div><iframe src="data:text/html,<style>body{background:orange}</style>"></iframe></div>
